The Federal Trade Commission sent letters to 45 people after receiving complaints from Public Citizen, Campaign for a Commercial-Free Childhood, and the Center for Digital Democracy, reports Billboard. The groups pointed out in their letters that Instagram “has become a platform for disguised advertising directed towards young consumers.” And that, according to the organizations, is against the law.

The letters explain that posts that endorse products without disclosing financial gains are against the law.

The advocacy groups requested an investigation into these matters and asked for actions to be taken to enforce regulations for non-disclosed advertising through “influencer” profiles on Instagram.

The complaints were sparked after the catastrophe that was the Fyre Festival.

Kendall Jenner, Emily Ratajkowski and Hailey Baldwin were among the influencers called, “Fyre Starters,” who promoted the event. They have all been named in lawsuits and could potentially face litigation for marketing the festival without disclosing financial compensation.

The complaint letter to the FTC also mentioned Instagram posts from Rihanna and One Direction, though neither of them were in follow-up letters the FTC wrote and released on May 4, following a Freedom of Information Act filed by Womens Wear Daily.

Though many of the Instagram posts have since been deleted, the FTC referenced them in their letters, which are on the government’s Freedom of Information Act portal.

“I am writing regarding your attached Instagram post by Sean Combs,” the letter to Diddy read. “You posted a picture of two bottles of AQUAhydrate water in what appears to be a car and he writes, ‘Lets GO!!! @aquahydrate #balance, #hydrate #try it” The letter continued: “We understand that you are an owner and director of AQUAhydrate,” which the FTC says should have been “clearly and conspicuously disclosed.”

To the CEO of the JSC Synergy Group, the FTC officer wrote, “I am writing to call your attention to the Attached Instagram post by [Akon] and by Jennifer Lopez. Akon posts a picture of two iced bottles of Beluga vodka in front of a blue body of water and writes, “Holidays with @vodkabeluga always great. #VODKABELUGA”.

Ms. Lopez posts a picture of herself with several bottles of Beluga vodka and writes, “#TBT to my Birthday weekend in Vegas! Thanks again @vodkabeluga #vodkabeluga,” they continued.

And a letter addressed to Luke Bryan care of Julie Colbert at William Morris Endeavor Entertainment said this, “I am writing regarding your attached Instagram post endorsing Cabela’s [a hunting, fishing and outdoor gear retailer]. You posted a picture of yourself in Cabela’s store holding a fishing rod. You wrote, “Which one should I get? #HFE” HFE is the name of Bryan’s clothing line which was named for his hit single “Huntin’ Fishin’ and Lovin’ Every Day.”

All the letters noted the need to disclose any “material connection between an endorser and the marketer of a product,” and included a copy of the FTC’s “Endorsement Guide.”